


Secret Santa comes in many forms

by Animillion



Category: Dr. STONE (Anime), Dr. STONE (Manga)
Genre: Blowjobs, Father/Son Incest, First Orgasm, M/M, SecretSanta2019TKS, Senkuu is 12, Shotacon, Size Difference, TKSevents, TheKingdomofShipping, christmas gifts, handjobs, i MIGHT be going to hell XD
Language: English
Status: Completed
Published: 2019-12-04
Updated: 2019-12-04
Packaged: 2021-02-26 06:01:37
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 1,851
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/21668644
Author URL: https://archiveofourown.org/users/Animillion/pseuds/Animillion
Summary: Senku knew Santa wasn’t real. He knew his dad was the one who gave up his car to get him all of those science tools. He wants to give back this year and thank his dad in a special way. He’s his lil secret Santa.
Relationships: Ishigami Byakuya/Ishigami Senkuu, Ishigami Senkuu/Ishigami Byakuya
Comments: 8
Kudos: 61
Collections: 2019 TKS Secret Santa





	Secret Santa comes in many forms

**Author's Note:**

  * For [KaiVonBrown](https://archiveofourown.org/users/KaiVonBrown/gifts).



> Inspired by my giftees prompt
> 
> Cute fluffy Christmas morning sex. Initiated by Senku.

Electrical heating made everything better. When the winter weather of the Christmas morning beat on the roof, you could always rely on the heat. Senku wakes up in that warmth. His mind ogles at the comfort he’s having right now. Cozy in his bed, wrapped up under rocket ship blankets. One of his eyes catches the time. It’s six am. The sun is just now rising, but it has entered his room already. 

_It’s Christmas._

Santa wasn’t someone he had believed in since last year when he found his fathers car had gone missing, and he had suddenly acquired so many new scientific items. The now 12 year old had figured out that it was his father who had gotten him those things. The older man had watched him go through each and every one of them. He listened to him with a patient smile and saw him bouncing on his feet when he finally was able to look through his telescope that Christmas night. 

Senku remembers having gotten halfway through a thank you letter to Santa. It was now somewhere in one of the study room drawers. The boy smiles. This year he wants to thank his Santa for real. Byakuya doesn’t know he knows Santa isn’t real. And knowing Byakuya, it’d crush him to find out something so innocent was gone inside him. But that wasn’t the only thing fleeting innocence inside this boy. 

Senku wiggles from out of the covers. He needs to do this before Byakuya wakes up and starts the day. His feet touch the still cold hardwood floor and he shivers. The problem in his pants that he’d been getting lately was also awake. Embarrassed, he feels he shouldn’t be. After all, what was about to happen was a bit more than just his little morning wood. 

He walks down the hall to Byakuya’s room. He’s trying to be as quiet as possible. Byakuya wasn’t a light sleeper, but he’s not a heavy one either. 

The door to his fathers room makes him wince. Of course it’d be that loud. Still, the man who lays on his futon seems so unbothered by it. Senku lets out a little breath. Okay. Good. 

He shuts the door behind him. Byakuya’s phone goes off, making him jump in surprise. The man turns, pressing his hand around on the nearby area until the alarm is ignored. He doesn’t notice Senku, not even bothering to open his eyes. A mumble of something or another comes out of him as his body relaxes again. 

The boy doesn’t waste time before he’s crawling into the futon. Byakuya looks like a mess when he’s sleeping. His mouth hangs open and an arm is thrown above his head. Thankfully his legs were apart, one straight and the other slightly bent. All that was missing was some snoring. Crimson eyes trail down the mans half naked body. Byakuya also has the same problem he has. 

Words go through Senku’s mind from a library book he had read about this. Boners were normal for kids like him going through puberty. Byakuya wasn’t a kid though. He was full grown and developed. The boy wants to know what it looks like. This was a present for Byakuya though. Sweat forms on his palms. Things would be easier if he were under the blanket. After all, he wants to give Byakuya a blow job. The boy manages to get under and back in his spot without alerting the sleeping man. 

He starts by pressing the hard length through his boxers. Byakuya shifts and Senku holds his breath. The other really was hard. And from the feeling of it, he was large too. Senku presses a kiss to the outline of his dick. It smells weird. Trying again, he takes his small hand to rub the clothed length. 

“Nnnrgh.” Byakuya makes a strange noise and shifts again. Senku doesn’t move from his spot between him. It surprises him when the others cock twitches on its own under his little hands. His fingers curl around the stretch band of Byakuya’s underwear and pull down. He couldn’t really see the others cock while in the dark of the covers. But the feeling of it was definitely not like his own. It was pulsating and long- squishy but stiff. Thick too. Senku wonders if he can get it in his mouth all the way. Probably not without hurting his jaw and throat. His face scrunches up at the thought. He is rubbing up and down Byakuya’s length with both hands now. 

A blow job as a present- he had heard an upper classman talking about something like that. Despite how skeevy and moronic they were, Senku was curious. He had researched it and felt almost embarrassment that he didn’t know. These were the things guys were supposed to know. Senku knew a ton of algebraic formulas and had even gotten the hang of morse code. Seems human engineering was next. He already knew a lot from making his dad that swim suit. But this.. 

“Senku?” He freezes. Fuck. Was his dad horny enough to believe it was a dream yet he wonders. He expects the covers to be thrown off of him but after a moment of silence he continues his stroking. The drops of precum coming from the head slip under his fingers, slicking his actions. The man moans. Senku grins in satisfaction at that. It was clear his father was enjoying his present. 

The boy leans down to press his lips to him. He opens his mouth and lets his tongue run up the underside before attempting to fit the head in his mouth. To his surprise it fits. However, he can only get the head and maybe half an inch in before his throat shuts off and tears well in his eyes. It doesn’t matter, Byakuya is moaning regardless. 

Senku feels his own little cock throbbing away in his pants. This was hot to him, and a little stone in his stomach feels almost wrong for it. 

“Senku~” 

The man moans his name and he smiles again. What a good turn out. Senku’s small, dainty hands work up and down the others cock, feeling his skin shift and his veins pulse. The angle is weird but Senku does his best to lick and lap all over his dick. The heat of his mouth causing Byakuya to gasp and groan. He doesn’t say much but Senku’s name. It feels like he wants to say more but is afraid to. 

Senku is suckling on the head of his cock when his arousal comes to a climax. The boy gasps and feels cum hit his face. Heat floods his cheeks. Was that it? Did Byakuya orgasm? 

The cock is twitching and the blood is pumping faster than before. Byakuya has his hips lifted while Senku strokes what’s left of him out. He’s breathing deep when he relaxes back on the futon. Senku wipes at the cum on his face. It’s salty and weirdly wet on his tongue. He doesn’t realize how hot he is under the blanket until Byakuya is sitting up and pulling it off of him. A shiver runs down his spine at the fresh air. Looking up at his father he can’t help but grin. The man looks rough, like he had just seen a ghost in the middle of getting married. He cups Senku’s face so soft the boy wondered if he was in trouble. 

“Senku.” 

“Yes?”

“What are you doing?”

“Giving you a blowjob.”

The father deadpans and Senku is still grinning at him. 

“Now why on _earth_ would you want to do that?” He doesn’t look mad.

Senku thinks for a minute. He blows his bang strand from tickling his nose and he feels the tip catch some of his facial.  
“I wanted to make you feel good- for your Christmas present.” 

Byakuya puts a hand to his face, obviously not knowing what to say. He opens his mouth but stops before saying anything at all. Instead his eyes look far down. Senku watches him and feels his face heat up again. His own little boner was still asking for attention. He squeezes his legs together and covers it with his hand. 

“I got a little excited too dad.” 

Byakuya sighs and runs his hand through the mess that was Senku’s hair. 

“Here Senku,” he lifts him by his arms and turns him to sit between his legs. 

The boy doesn’t like the other’s softening cock pressing against his back. He likes him spreading his legs out and pulling his pajama shorts down even less. He blushes. Compared to Byakuya, his small hard on might as well be non existent. Byakuya’s hand engulfs it and Senku gasps. 

“D-dad?”

“Can I reciprocate the present, Senku?”

“Is there any point in asking at this point?” That was a yes. Senku couldn’t believe how warm it was inside his large fist. He relaxes against the other’s chest as the man strokes him up and down. The sensations are new and he squeezes his eyes shut tight. His dad was really good at this. Well, considering his size he really didn’t have to be. 

“Thank you for your present, I got you dirty though.” Byakuya presses a kiss to the other’s hair. Senku whines and balls the blankets in his fist. The blanket was scattered, surrounding them in a broken cocoon. It was warm. Byakuya’s hand was warm. And Senku felt so _warm_. 

“Dad-B-Byakuya- I-“ He knew it wouldn’t take much to cum himself. But he didn’t know it would feel so good. He spills over in Byakuya’s fist, moaning and lithe body shaking. He feels like he’s in that state forever. Where his heart is beating in his ears and his body is swirling with some new kind to ecstasy. And the noises outside fade into nothing. It’s just them on Christmas morning, and there is nothing else. 

“You came a lot.” Byakuya chuckles. That’s the first thing the boy can hear as he comes back to earth. The man is opening his hand to reveal the mess Senku had made in it. The boy looks up at him, dazed. Is this what he made his dad feel like moments ago? The thought makes him happy. 

“Merry Christmas dad.”

“Merry Christmas Senku, now lets get cleaned up and have breakfast.” His dad moves him off of him. 

Senku gets up, wobbling on his feet a little. Air hits his face and he remembers he has cum on his cheeks. He can’t really tell what his dad is feeling. But he’s not mad. If anything, Senku would say he’s overjoyed. He has that constant little quirk in his lips and his eyes look at him soft. Like he just wants to pull the covers over them and sleep again while holding his son. He helps Senku shower off and into a nice soothing bath while he makes breakfast. 

The boy sits there, warm and still a little dazed, hoping that maybe soon he will be able to be Santa again.

**Author's Note:**

> Okay so tbh I was gonna stick to two gifts but I ended up getting inspiration for the first prompt you gave! So merry Christmas Kai!!! XD I hope you liked the second ByakuSen fic. It’s been a HOT minute since I’ve written full on shotacon so I hope it’s tasteful enough :p
> 
> I also hoped everyone else had fun reading this!!! ^w^
> 
> If you’re interested in joining TKS discord server  
> [Click here!](https://discord.gg/T4sYthM)


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